There are several well-known devices and processes for brewing coffee.
Arguably, commercial expresso machines of the type found in cafes and coffee shops produce the best coffee. While some manufacturers are now making small expresso coffee machines for domestic use, penetration into the domestic market is limited due to the relatively high cost of the machines.
Drip type coffee brew machines are in relatively common domestic use for making coffee. This type of machine relies on heated water dripping through fine ground coffee beans held within a filter. The water saturates the coffee grounds and after passing through the filter falls into an underlying jug which typically sits on a heated base. This type of machine makes good quality coffee although if care is not taken, over an extended period, the heat applied to the jug will “cook” the coffee thereby reducing its quality.
Percolators provide yet another device for making coffee. A typical percolator is provided with an upper and lower reservoir separated by a replenishable filter basket holding ground coffee. The lower reservoir of the percolator is heated on a stove causing the water to bubble through the basket on its passage to the upper reservoir. The percolator needs to be watched carefully and removed from the heat source after all the water has risen from the lower reservoir to the upper reservoir.
Recently “plunger coffee” has become popular. A typical plunger coffee maker comprises a glass vessel and a plunger having a filter mesh supported at a lower end of a stem, the upper end of the stem being provided with a handle and a heat shield. When making plunger coffee, initially coffee grounds are spooned into the vessel and the vessel filled with hot water to a level below the top of the vessel. The filter portion of the plunger is inserted into the vessel at a position above the level of the water. The heat shield is then slid down the stem and engaged with the top of the vessel. The plunger is maintained in this position for a period of time to allow the ground coffee to be saturated/infused. Thereafter, the handle is depressed pushing the filter to the bottom of the vessel trapping undissolved coffee grounds between the filter and the bottom of the vessel. The coffee can then be poured from the vessel to a cup and mixed with sugar, milk or cream as required.
Perhaps the overwhelmingly common way of making coffee is to use “instant coffee grounds” spooned from ajar into a cup into which hot water is added. The instant coffee grounds are made from highly processed coffee beans so that they dissolve and for this reason provide a potentially poorer taste.